Patent GB-856897-A (GB)
Title: Improvements in or relating to compressed air brakes for railway rolling stock
IPC: B60T13/66
Filed: 1958-08-06
Abstract: 856,897. Compressed-air brakes. VERWALTUNGSGESELLSCHAFT DER WERK ZEUGMASCHINENFABRIK OERLIKON. Aug. 6, 1958 [Aug. 9, 1957], No. 25151/58. Class 103 (1). In a compressed-air brake for railway vehicles, a supply reservoir charged from the brake pipe is connected to the brake cylinder either through an indirectly acting control member subject to pressure difference between the brake pipe and a constant pressure reservoir, or through a directly-acting control member which on initiation of braking supplies air from the constant pressure reservoir to a relay valve controlling the connection of the supply reservoir with the brake cylinder. The direct acting control member 10, Fig. 2, includes an electric pilot valve 14 having a solenoid 16 energized from the driver's brake valve 70, Fig. 1, through a conductor 7 to raise armature 17 and valve body 18 to first close chamber 25 from atmosphere via body 18 and port 27 and then raise the valve 21 to supply air from constant pressure reservoir 13 to the chamber 25 and to chamber 26 of a relay valve 15 to raise valve member 31 to first close chamber 35 and the brake cylinder 8 from atmosphere via port 37 and then open valve 29 to supply compressed-air from supply reservoir 12 to brake cylinder 8 via pipe 36 and double non-return valve 9. Springs 30, 22, 23 return the components of member 10 to the shown position on de-energization of solenoid 16 to vent the brake cylinder. In the indirectly-acting control member 11, a reduction in train pipe-pressure initiated in the driver's pilot valve 71, Fig. 1, acts via pipe 48 in chamber 47 of quick-service valve 38; the control pressure from reservoir 13 acting in chamber 42 raises a diaphragm 41 to open valve 44, 46 to connect the train pipe 6 to atmosphere via port 49 to propagate a further pressure reduction in the train pipe along the train. The train pipe-pressure also acts in chamber 53 of control valve 39, the constant pressure in chamber 52 raising diaphragm 56 and valve member 59 to first close communication of the brake cylinder 8, chamber 54 and chamber 80 of valve 38 with atmosphere via port 62 and then to open valve 64 to supply air from reservoir 12 to the brake cylinder via non-return valve 9, this pressure acting in chamber 68 of the charging valve 40 to close valve 69 to shut off the constant pressure reservoir 13 from the train pipe 6. Also, the pressure acts in chamber 80 of valve 38 to close the valve 81, 82 to prevent further venting of the train pipe 6. In the driver's brake valve 71, Fig. 1, with the lever 76 in the running position, a constant pressure reservoir 92 is charged from a main reservoir 97 via a valve 95 held off its seat 94 by a spring 88 until the pressure in reservoir 92 and chamber 93 reaches normal pressure, the spring 88 holding the valve body 90 against the valve 95 to seal off the connection to atmosphere. Pressure in chamber 93 acts in chamber 113 of a feed valve 78 to raise the valve body 112 to open valve 116 to permit flow from reservoir 97 to chambers 114 and 101, and via a valve 102, 103 restricted by the shoulder 108, to the brake pipe 6. On equalizing of pressure in the chambers 114, 113 the valve 116 closes. The supply reservoir 12 being charged via restrictions 66a and one-way valve 66, Fig. 2, and the constant pressure reservoir via pipe 48, chamber 53 of control valve 39, chamber 69 of charging valve 40 and pipe 24. For brake application, the lever 76 is rotated to move cam 86 up a sloping face 87 and relieve pressure on the spring 88, the diaphragm 89 is then raised by pressure from the constant pressure reservoir 92, to connect chamber 93 and chamber 113 of feed valve 78 to atmosphere via ports 99 and 91. The pressure drop in chamber 113 causing valve body 112 to move down to connect the chambers 101, 114 and the brake pipe to atmosphere. For brake release, the lever 76 is turned to an initial charge or a braking position in which a cam 107 on the body 79 raises the valve 103 to move a restriction 108 from the seat 102, the valve 95 being opened by spring 88 to recharge the system as described above. In Figs. 3 and 4, not shown, the driver's electric brake valve 70 is replaced by a compressed-air valve supplying air to the valve 14 which has a diaphragm acting on the valve body 18; and in Fig. 5, not shown, the double non-return valve 9 and a relay valve 15 of the direct member 10 are replaced by a single relay valve common to both members 10 and 11, whilst in Fig. 6, not shown, this relay valve is replaced by a second relay valve and a double non-return valve, a manually-actuated cock being present adjacent the control valve to either vent or pressurize one of its chambers to give two ranges of brake cylinder pressure depending on the setting of the cock.